HIV infection in Addis Ababa, the capital city of Ethiopia, is projected to be approximately 15.6% and no information exists on how HIV and HIV-related diseases impact the CNS of the Ethiopian population. The main scientific objectives of this prospective neuropathological study are to determine the frequency and unique characteristics of CNS involvement from the brains of HIV autopsy cases in Addis Ababa. Accomplishing the scientific objectives will: 1) transfer technology to educate and train pathologists in Ethiopia to use autopsy material for the diagnosis and pathological characterization of HIV and HIV- associated CNS involvement, 2) create a permanent resource for documenting pathological profiles of HIV patients at various stages of disease, and 3) establish pathological confirmation of clinical diagnosis or suspected HIV. AIM I: Establish collaborative system between Addis Ababa University School of Medicine and the University of California San Diego for the collection of autopsy tissues from the Ethiopian population to 1) determine the percentage of HIV infection and 2) HIV associated CNS opportunistic infections and/or neoplasms. AIM II: Determine the frequency of CNS involvement by M. tuberculosis in HIV+ patients from this study and describe pathological patterns of CNS tuberculosis in relation to HIV CNS pathology. For this purpose, post-mortem CNS tissues will be collected from 200 Medico-legal Forensic Pathology adult autopsy cases that consist of a broad cross-section of the Ethiopian population in Addis Ababa and will include both sudden deaths and deaths from pre-existing illness. Tissues will be processed for neuropathological diagnoses to determine patterns of HIV and HIV-associated CNS involvement. A database describing patient demographics, and including tissue sections with detailed neuropathological diagnoses will be constructed. These studies will provide for the first time neuropathological characterization of the natural history of HIV neuropathogenesis in Ethiopian. This collaborative effort between the University of California San Diego and Addis Ababa University School of Medicine will contribute to the overall goal of increased research capacity in Ethiopia by providing a permanent and expandable technological resource for the education of medical personnel in Ethiopia regarding HIV neuropathogenesis. Increased understanding of HIV neuropathogensis will contribute to the improved treatment and management of HIV patients in Ethiopia.